This invention generally relates to the art of electrical connectors and, particularly, to the terminals for such connectors. Specifically, the invention relates to a method of manufacturing or fabricating electrical terminals, including terminals used in a terminal module.
A typical electrical connector includes an insulating or dielectric housing which mounts a plurality of terminals. The connector is mateable with a complementary mating connector or other connecting device wherein the terminals engage or mate with the terminals of the complementary connector.
It is well known in the prior art to manufacture the terminals for electrical connectors by stamping and forming the terminals from a continuous sheet or strip of metal material. During the stamping or punching operation, portions of the sheet metal material are removed, leaving the profiles of the terminals which subsequently are formed into their desired configurations. The terminals typically are joined by a carrier strip and/or a tie bar of the sheet metal material to facilitate moving the material through a sequence of processing stations and to facilitate subsequent fabrication operations. For instance, the stamped and formed terminals may be transported to a processing station whereat the terminals are overmolded by a dielectric housing to form a terminal module. The entire module, including the overmolded terminals, then can be unitarily inserted into an electrical connector housing.
Because of the ever-increasing miniaturization of electrical connectors and the continuing demand for high density terminal arrays, stamping and forming processes continue to create barriers in achieving these goals. One problem involves the stamping or punching operation, itself. As stated above, when the sheet metal material is stamped into a blank of a desired configuration to subsequently form the terminals, sheet metal material inherently is removed from between the terminals, leaving their desired profiles. Therefore, the density or pitch between the respective terminals is limited by the widths of the punching tool portions and the width of the terminal portion or solder pad and the resultant strength of the solder joint formed being reduced. In other words, the terminals cannot be stamped in positions immediately adjacent to each other. The present invention is directed to solving these problems by a manufacturing method which includes a sequence of fabricating steps including both stamping and shearing processes which results in higher density terminal arrays and/or wider terminal portions because metal material is not removed between the portions.
An object, therefore, of the invention is to provide a new and improved method of manufacturing electrical terminals, including a terminal module.
In the exemplary embodiment of the invention, the method, generally, includes the steps of stamping from a sheet of metal material a blank for a plurality of elongated terminals having contact portions at one end and terminal portions at the other end and joining the terminals by a tie bar intermediate the ends. The contact portions of the respective terminals are separated from each other by the stamping step. The terminal portions remain joined in the sheet metal material. The blank then is sheared to separate the terminal portions. The tie bar then is removed to separate the terminals.
The invention also contemplates a method of manufacturing a terminal module using the steps outlined above. In particular, a dielectric housing is overmolded about the terminals intermediate the ends thereof, with the tie bar being located outside the housing. The tie bar subsequently can be cut to separate the terminals to insulatingly isolate the terminals by the dielectric housing.
As disclosed herein, the method includes the step of forming at least some of the terminals out of the plane of the sheet metal material after the shearing step. Specifically, the terminal portions of the terminals are formed such that alternating terminal portions are disposed in one plane and the remaining alternating terminal portions are disposed in a second plane. At least some of the terminal portions are formed to one side of the sheet metal material. With the terminal portions in two planes, the portions can be used as solder pads for engaging circuit traces on opposite sides of a printed circuit board at the edge thereof.
Still further, the preferred embodiment illustrated herein includes a carrier strip joining one end of the terminals after the stamping step, with finger portions projecting inwardly from the carrier strip. During the forming step, the finger portions are formed out of the plane of the sheet metal material on the same side thereof as some of the terminal portions. Thereby, the finger portions provide support for a transport sheet and protect the formed terminal portions.
Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings.